Vulcanizing process.



UNITED STATES PATENT OFFICE.

CHESTER E. ANDREWS, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE WALKER .GHEMICAL COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION. OF

DELAWARE.

. VULCANIZING PROCESS.

\ 1,280,940. Specification of Letters Patent.

No Drawing.

To aZZ 'whom-it may concem:

Be 1t known that I, CHESTER E. ANDREWS, acitizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Vulcanizing Processes, of which the following is a specification.

The present invention relates to vulcanization, and has been found to be of special value in the case of the vulcanization of rubber. While I describe this invention as applicable to rubber, it is to be understood that I do not confine the invention thereto, since it is also applicable in the vulcanization of other gums of a somewhat similar nature.

It has heretofore been proposed to add to the mixture of sulfur and rubber, prior to the vulcanizing operation, a small amount of anilin, to act as a catalyst, during the operation, whereby the time necessary for the vulcanizing operation is greatly reduced, and it. is claimed that a superior product is produced.

In the prior art, several other materials have been proposed as substitutes for the anilin, originally proposed by Price, but such materials in general have not been found to be materially better than the anilin, and

in many cases it has been found that such substitutes are not nearly as good as anilin.

So far as I am aware, such anilin substitutes have not come into extended use in the art, presumably on account, either of the greater expense attending their use, or else on account of the fact that the products are not as good as when anilin is employed.

I have now found that amino cymene, a substance having the formula:

H104 OHa is in some respects better than anilin for the purpose. I

This material can be cheaply prepared,

by the use of anilin as Application filed February 27, 1918. Serial No. 218,446.

also is found to have some specific advantages over anilin, especially in that the, vulcanized rubber (a) is capable of greater stretch, (b) is more resistant to atmospher1c oxidation (hence (c) has a better color, than that roduced a vulcanization catalyst. The amino cymene also is found to be somewhat quicker-in its action, 71. 0. it is not necessary to heat the mixture as long, in the vulcanization operation (the same temperature and pressure being used) as when an1l1n alone is used. Less of the amino cymene, than of anilin, will produce satisfactory results.

Without limiting myself to details, I e the following example to more fully expldin the invention, and how the same is to be performed (the parts being by wei ht) To a mixture of 100 parts 0% raw unvulcanized rubber and sulfur, there areadded about 5 parts of amino cymene, and the mixture well kneaded. The material, or any desired part thereof (which ma be molded into the desired form if desired is placed in a vulcanizer and heated under pressure to about 130 to 150 (1, for 1 to 2 hours. If the vulcanizer is first filled with steam, or a little water placed in the bottom thereof before the heating, a better result is secured.

The proportions of sulfur and rubber in the initial material may be varied between wide limits, as is'well known in the art. The proportion of amino cymene can be varied between widelimits, say from .5% to 5% giving good results, the larger amounts giv- 1n quicker vulcanization.

longer-lived) and terial which comprises heating, under vulcanizin conditions, a mixture comprisin such ru her-like material, a sulfur materia and amino methyl isopropyl benzene.

2. The process which comprises vulcanizing rubber in the presence of amino cy- 5. A vulcanized rubber compound conmene. taining sulfur and amino cymene as trans- 3. Vulcanized rubber containing amino formed by the heat of vulcanization. v w cymene or its derivatives. In testimony whereof I aflix my signa- 5 v 4:. In the process of ulcanizing, the additure.

tion of amino cymene as an accelerator of l the vulcanizing action. CHESTER E. ANDREWS. 

